Question

Diego is trying to lift a piano to the second floor of his house. Diego uses a pulley system and gives a big lift to the piano. The piano moves upward, then stops, and then it starts to fall to the ground.
Which list best describes the forces on the piano in the proper order?

A.positive force, balanced force, negative force
B.negative force, balanced force, positive force
C.positive force, unbalanced force, negative force
D. Negative force, unbalanced force, positive force

Answer 1

Answer:

Option A is correct

Explanation:

As the piano moves upwards, the net force acting on the piano is

Fnet = T - mg

Where T be the tension in the string and mg be the weight of piano.

Here Fnet is always positive because piano is moving up and upward direction is taken as positive.

When the piano stops, the net force acting on the piano is zero.

Fnet = 0

When the piano moves downwards, the net force acting on the piano is

Fnet = mg - T

As the net force is acting downwards, so the direction of force is negative.

Answer 2

The Answer is A becuase the piano moving up is is going in a positive way whe it stops the forces are equal then when it falls the forces are negative